insidious

adjective

Definition of insidiousnext
as in treacherous
formal causing harm in a way that is gradual or not easily noticed Most people with this insidious disease have no idea that they are infected. an insidious enemy

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Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of insidious Given the chance to go big with his take on insidious zealotry, the Harold & Kumar star is both charming and gargantuan. — David Fear, Rolling Stone, 28 Sep. 2026 For The Times) New research in California’s San Joaquin Valley finds valley fever fungus thriving in urban areas in rodent burrows, revealing a wider, more insidious footprint. — Susanne Rust follow, Los Angeles Times, 24 Sep. 2026 Duckworth also faced backlash from critics who argued that her message was, at best, a series of hollow exhortations to simply try harder and, at worst, an insidious form of victim-blaming that ignored structural inequality. — Meghan O’Gieblyn, New Yorker, 14 Sep. 2026 If anything, this makes those insidious Fridays insignificantly safer than the state average for the period. — Mike McRae 08, New Atlas, 8 Sep. 2026 See All Example Sentences for insidious
Recent Examples of Synonyms for insidious
  1. treacherous
  2. subtle
  3. perfidious
  4. deceptive
  5. false
  6. misleading
  7. deceitful
  8. incorrect
Adjective
  • Last month, the Coast Guard and Customs encountered several migrant ventures, some deadly, off the Dominican Republic and in the treacherous Mona Pass, between Hispaniola and Puerto Rico.
    — David Goodhue, Miami Herald, 29 Oct. 2026
  • Time is running out for a Republican Party led astray by a president whose treacherous behavior mimics those assigned to the lowest level of Dante’s hell.
    — Bob Kustra, Chicago Tribune, 22 Oct. 2026
Definition of treacherous
Adjective
  • Ask whether a blunt edge, subtle graduation or minimal layering would best preserve fullness for your particular hair.
    — Ashley Lynch, Miami Herald, 28 Oct. 2026
  • Smaller rollers tend to produce tighter curves, while larger ones create looser waves or more subtle shaping.
    — Ashley Lynch, Fort Worth Star-Telegram, 28 Oct. 2026
Definition of subtle
Adjective
  • Logan Marshall-Green as Melanthius Melanthius is a perfidious goatherd who sides with Antinous.
    — Hannah Abraham, Forbes.com, 18 July 2026
  • This is perhaps the most perfidious practice of this sort of politics.
    — David M. Drucker, Twin Cities, 3 June 2026
Definition of perfidious
Adjective
  • Supporters say licensing will give California the authority to act on any complaints, and to investigate and penalize companies for unfair or deceptive practices.
    — Audrey McGlinchy, Los Angeles Times, 28 Oct. 2026
  • Esparza pushed back against the claim that the group was being deceptive.
    — Stephen Hobbs, Sacbee.com, 27 Oct. 2026
Definition of deceptive
Adjective
  • The men stopped short of signing the oath required for vouching, but Moriarty said that giving false names and starting the process was enough to justify the felony charges.
    — Mark Vancleave, Los Angeles Times, 29 Oct. 2026
  • Bhengura faces a maximum of five years in prison on the false statements of citizenship in order to register to vote count and a maximum of one year in prison on the voting by an alien in a federal election count.
    — Emerson Clarridge, Fort Worth Star-Telegram, 29 Oct. 2026
Definition of false
Adjective
  • Soon afterward, an investment-research firm alleged that the company had made misleading claims about pre-orders.
    — Dan Kaufman, New Yorker, 27 Oct. 2026
  • Trump has described the broadcast as false, misleading and defamatory under Florida law.
    — Brittney Melton, NPR, 23 Oct. 2026
Definition of misleading
Adjective
  • What readers are saying The comments reflect a strong criticism of James O'Keefe and his methods, with many labeling him as deceitful and manipulative.
    — Scott Nover, Washington Post, 22 Oct. 2026
  • Hanuman inspires him to avenge the rape of his mother by a corrupt policeman working for a deceitful Hindu nationalist spiritual leader.
    — Sohini Sarah Pillai, The Conversation, 14 Oct. 2026
Definition of deceitful
Adjective
  • Use safer payment methods When shopping online, paying with a credit card generally gives you stronger protections if an order never arrives or a charge is incorrect.
    — Kurt Knutsson, FOXNews.com, 27 Oct. 2026
  • The figures represent requests for financial assistance, not necessarily complaints about incorrect water bills.
    — Jamal Goss, CBS News, 27 Oct. 2026
Definition of incorrect

Browse Nearby Words

inside tracks
insidious
insidiously
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Cite this Entry

“Insidious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/insidious. Accessed 31 Oct. 2026.

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